[PATCH v4 4/6] bcm2835: Dynamically calculate bytes per pixel parameter

[Ivan T. Ivanov]

brcm,bcm2708-fb device provided by firmware on RPi5 uses
16 bits per pixel, so lets calculate framebuffer bytes
per pixel dynamically based on queried information.

Tested to work for RPi2b v1.2, RPi3b v1.3, RPi4b v1.1,
RPi2 Zero W, RPi5b v1.0.

Signed-off-by: Ivan T. Ivanov <iivanov at suse.de>
---
 drivers/video/bcm2835.c | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/drivers/video/bcm2835.c b/drivers/video/bcm2835.c
index 14942526f1..63efa762db 100644
--- a/drivers/video/bcm2835.c
+++ b/drivers/video/bcm2835.c
@@ -16,7 +16,7 @@ static int bcm2835_video_probe(struct udevice *dev)
 	struct video_uc_plat *plat = dev_get_uclass_plat(dev);
 	struct video_priv *uc_priv = dev_get_uclass_priv(dev);
 	int ret;
-	int w, h, pitch;
+	int w, h, pitch, bpp;
 	ulong fb_base, fb_size, fb_start, fb_end;
 
 	debug("bcm2835: Query resolution...\n");
@@ -41,9 +41,23 @@ static int bcm2835_video_probe(struct udevice *dev)
 					DCACHE_WRITEBACK);
 	video_set_flush_dcache(dev, true);
 
+	bpp = pitch / w;
+	switch (bpp) {
+	case 2:
+		uc_priv->bpix = VIDEO_BPP16;
+		break;
+	case 4:
+		uc_priv->bpix = VIDEO_BPP32;
+		break;
+	default:
+		printf("bcm2835: unexpected bpp %d, pitch %d, width %d\n",
+		       bpp, pitch, w);
+		uc_priv->bpix = VIDEO_BPP32;
+		break;
+	}
+
 	uc_priv->xsize = w;
 	uc_priv->ysize = h;
-	uc_priv->bpix = VIDEO_BPP32;
 	plat->base = fb_base;
 	plat->size = fb_size;
 
-- 
2.35.3